Starbucks Coffee Co. will buy Teavana Holdings Inc. for $620 million in cash as the coffee giant powers deeper into the tea market.

The $15.50-a-share price is lower than the $17 a share at which Teavana was priced for its public debut last July. The stock opened at $28.95 a share but has since slumped heavily to close at $10.13 a share Tuesday.

But after Starbucks’ afternoon announcement Wednesday, Teavana shares surged as much as 59% to $16.06 a share.

Starbucks said it plans to expand Teavana’s existing 300 mall-based stores while adding a “high-profile neighborhood store concept.” The tea company was attractive, Starbucks executives said, because of its industry expertise and global sourcing network.

Atlanta, Ga.-based Teavana was founded in 1997 and offers more than 100 kinds of premium loose-leaf teas, artisanal tea equipment and other merchandise.

The global tea industry is valued at $40 billion and is growing fast, according to Starbucks.

The Chicago Cubs on Tuesday sought City Hall permission to expand construction hours at Wrigley Field, with bleacher work falling well behind schedule on the team's $375 million ballpark renovation project.